It wasn't a nightcrawler. It was labeled as a superworm. It does have pincer jaws, so I crushed their heads from that point on. Kermit didn't seem to suffer any ill effects. It was just a bit scary to see.
i feed something similar called fruit grubs, like you i nip there heads before i feed them as they give a hell of a bite, but even with there heads nip they still wriggle inside the frog for a while,